Downforce sweeper

ABSTRACT

A device for collecting debris from a surface, comprising a catcher and a lifting ramp, wherein the lifting ramp is located forward of the catcher such that when the device is moved over a ground surface, debris on the ground surface passes upwardly over the lifting ramp onto the catcher, wherein the lifting ramp is shaped as an aerofoil to create downforce on the lifting ramp toward the ground surface from air moving across the aerofoil under said movement.

FIELD OF THE INVENTION

The present invention relates to a sweeper for sweeping a ground surface and more specifically, but not exclusively, to a device for collecting foreign object debris from a surface such as an aircraft runway, racetrack, road, or other surface.

BACKGROUND OF THE INVENTION

It is known to provide a device for the collection of debris from a ground surface in the form of an airfield sweeper such as the one available under the trade mark FOD*BOSS. Such a device is described in International Publication No. WO96/09440 as made by the present inventor, and the entirety of that document is incorporated herein by reference.

Although the airfield sweeper which forms the subject of WO96/09440 has provided significant advantages in removing foreign object debris from aircraft runways so as to improve safety and save equipment damage, the applicant has identified that it would be further advantageous for airfield sweepers to have an even greater improved ability to remove foreign object debris from a ground surface.

Examples of the present invention seek to provide an improved sweeper which is able to provide increased efficiency and effectiveness in sweeping foreign object debris from ground surfaces such as aircraft runways, roads, racetracks and military areas.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention there is provided a device for collecting debris from a surface, comprising a catcher and a lifting ramp, wherein the lifting ramp is located forward of the catcher such that when the device is moved over a ground surface, debris on the ground surface passes upwardly over the lifting ramp onto the catcher, wherein the lifting ramp is shaped as an aerofoil or spoiler to create downforce on the lifting ramp toward the ground surface from air moving across the aerofoil or spoiler under said movement.

Preferably, the aerofoil is inverted so as to create downforce rather than lift.

Preferably, the device includes an agitator forward of the lifting ramp and an opening between the agitator and the lifting ramp, whereby, under said movement over the ground surface, said debris on the ground surface passes through the opening and onto the catcher via the lifting ramp.

Preferably, the catcher is a catcher platform.

In a preferred form, the device includes a single aerofoil.

In an alternative form, the device includes a plurality of aerofoils for creating downforce on the device toward the ground surface from air moving across the aerofoils under said movement. More preferably, the device includes a pair of aerofoils, including a first aerofoil in the form of said lifter ramp and a second aerofoil in the form of an additional lifter ramp mounted forwardly of said lifter ramp.

In one particular form, the additional lifter ramp is located intermediate the opening such that a forward opening portion of the opening is located forward of the additional lifting ramp and a rearward opening portion of the opening is located rearward of the additional lifter ramp.

Preferably, the device includes a tow hitch for attaching the device to a towing vehicle.

Preferably, the device includes a generally planar member having at least a portion thereof defining an undersurface of the device formed of a conformable material such that when the device is moved over the ground surface with the undersurface in contact with the ground surface the undersurface is caused to locally conform to undulations in the ground surface.

The catcher may form an upper surface of the device.

Preferably, the portion is formed from a flexible layer. The portion may be formed from an open mat of sinuous fibres. The portion may comprise artificial grass material. The conformable material may comprise a brush-like structure.

In a preferred form, the conformable material has bristles being constituted, and positioned with respect to the opening, whereby when the device is moved over the ground surface with the bristles in contact therewith, debris on the ground surface is agitated by engagement with the bristles and caused to pass upwardly through the opening to the catcher for collection thereon.

In accordance with another aspect of the present invention, there is provided a device for collecting debris from a surface, comprising a catcher and a lifting ramp, wherein the lifting ramp is located forward of the catcher such that when the device is moved over a ground surface, debris on the ground surface passes upwardly over the lifting ramp onto the catcher, wherein the device includes an aerofoil to create downforce on the lifting ramp toward the ground surface from air moving across the aerofoil under said movement.

Preferably, the aerofoil is in the form of a wing mounted atop at least one support to support the aerofoil in an airflow above a level of the lifting ramp.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of non-limiting example only, with reference to the accompanying drawings in which:

FIG. 1 is a cross-sectional diagrammatic view of a device for collecting debris in accordance with a first embodiment of the present invention;

FIG. 2 is a top perspective view of a portion of a device for collecting debris in accordance with the first embodiment of the present invention;

FIG. 3 is a cross-sectional diagrammatic view of a device for collecting debris in accordance with a second embodiment of the present invention;

FIG. 4 is a side perspective view of a device for collecting debris in accordance with the second embodiment;

FIG. 5 is a perspective view of the device for collecting debris of FIG. 4; and

FIG. 6 is a perspective view of a device for collecting debris in accordance with a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 to 6 of the drawings, there is shown an improved device for collecting debris from a ground surface. Advantageously, the device has one or more aerofoils and/or spoilers to provide downforce to the device created by airflow as the device is moved along a ground surface so as to improve the efficacy of the device in collecting debris from the ground surface.

More specifically, with reference to FIGS. 1 and 2, there is shown a device in accordance with a first embodiment of the present invention which has a single wing blade. The device 10 for collecting debris from a ground surface 12 comprises a catcher 14 and a lifting ramp 16, wherein the lifting ramp 16 is located forward of the catcher 14 such that when the device 10 is moved over the ground surface 12, debris on the ground surface 12 passes upwardly over the lifting ramp 16 onto the catcher 14. In the diagram shown in FIG. 1, the device 10 is arranged to move from left to right across the drawing such that the debris is caused to rise upward along the lifting ramp 16 owing to the movement of the device 10 together with the inertia of the debris. The lifting ramp 16 is shaped as an aerofoil 18 or spoiler to create downforce on the lifting ramp 16 toward the ground surface 12 from air moving across the aerofoil 18 or spoiler under said movement.

In particular, the lifting ramp 16 is provided with a substantially straight upper surface 20 and a curved lower surface 22 such that air flow across the lower surface 22 has further to travel than the air flowing across the upper surface 20, therefore creating lower pressure beneath the aerofoil 18, resulting in downforce on the lifting ramp 16. The air trajectory over the upper surface 20 is depicted by airflow line 24 whereas the airflow under the lower surface 22 is represented by airflow line 26. Accordingly, the air trajectory is labelled in this way by reference numerals 24 and 26 in FIG. 1. The aerofoil 18 is in the form of a reverse wing (having a longer air trajectory path at its lower surface and a shorter air trajectory path at its upper surface) which creates downforce at high speed. The lifting ramp 16 may also be provided with horizontal ridges 28 to assist in preventing debris from falling downward along the lifting ramp 16. Advantageously, owing to the downforce on the lifting ramp 16 toward the ground surface 12, a lower edge of the lifting ramp 16 is brought closer to the ground surface 12, thereby increasing the ability of the lifting ramp 16 in picking up debris from the ground surface 12.

As will be appreciated by a person skilled in the art, the aerofoil 18 is in fact arranged as an inverted aerofoil such that it creates downforce rather than lift on the lifting ramp 16.

The device 10 includes an agitator 30 forward of the lifting ramp 16 and an opening 32 between the agitator 30 and the lifting ramp 16, whereby, under the movement of the device 10 over the ground surface 12, the debris on the ground surface 12 passes through the opening 32 and onto the catcher 14 via the lifting ramp 16. The catcher 14 may be in the form of a catcher platform 34.

FIG. 2 shows a plastic moulding of the device 10 which includes the lifting ramp 16 and also defines the opening 32.

Although FIGS. 1 and 2 depict an embodiment of the device 10 which includes a single aerofoil 18, other examples of the present invention may include more than one aerofoil. Such an example is the second embodiment of the invention which is depicted in FIGS. 3 to 5. In this form, the device 10 includes a plurality of aerofoils for creating downforce on the device 10 toward the ground surface 12 from air moving across the aerofoils under the movement of the device 10 over the ground surface 12. In particular, the device 10 shown in FIG. 3 includes a pair of aerofoils (a double wing blade), being a first aerofoil 18 in the form of the lifter ramp 16 and second aerofoil 36 in the form of an additional lifter ramp 38 mounted forwardly of the lifter ramp 16. Similarly, in the example shown in FIG. 3, the device 10 is arranged to move in a left-to-right direction across the drawing.

Similarly to FIG. 1, the air trajectory in FIG. 3 is labelled by reference numerals 24 (upper air trajectory) and 26 (lower air trajectory) for each of the first aerofoil 18 and the second aerofoil 36. Each of the aerofoils 18, 36 is in the form of a reverse wing (having a longer air trajectory path at its lower surface and a shorter air trajectory path at its upper surface) which creates downforce at high speed.

The additional lifter ramp 38 is located intermediate the opening 32 such that a forward opening portion 40 of the opening 32 is located forward of the additional lifting ramp 38 and a rearward opening portion 42 of the opening 32 is located rearward of the additional lifter ramp 38.

FIGS. 4 and 5 show photographs of a sample device 10 in accordance with the second embodiment shown in FIG. 3. As can be seen, the central moulded portion of the device 10 defines the lifting ramp 16, the additional lifter ramp 38 as well as the forward opening portion 40 and the rearward opening portion 42. The central moulded portion may be formed in two (or more) parts which are tied together or hinged, as shown. Alternatively, the central moulded portion may be formed as a unitary structure. A forward end of the central moulded portion is attached to a forward agitator mat, whereas a rear end portion of the central moulding is attached to a rear agitator mat.

The catcher 14 may simply form an upper surface of the device 10, which may have a cover, or at least a retaining ledge, to retain the debris on the catcher 14 and to prevent the debris from falling off a rear end of the device 10. At a forward end, the device 10 may have a tow hitch (not shown) for attaching the device 10 to a towing vehicle. The device 10 may include a generally planar member having at least a portion thereof defining an undersurface of the device 10 formed of a conformable material such that when the device is moved over the ground surface 12 with the undersurface in contact with the ground surface 12, the undersurface is caused to locally conform to undulations in the ground surface 12. This portion of the planar member may be formed from a flexible layer in the form of an open mat of sinuous fibres, as in the forward agitator 30 shown in FIG. 1 and a rear agitator shown beneath the catcher 34. The portion may comprise artificial grass material and the conformable material may comprise a brush-like structure. The conformable material may have bristles which are formed and positioned such that when the device 10 is moved over the ground surface 12 with the bristles in contact with the ground surface, debris on the ground surface 12 is agitated by engagement with the bristles and caused to pass upwardly through the opening 32 to the catcher 14 for collection thereon.

With reference to FIG. 6, there is shown a device 10 for collecting debris 10 which is generally similar to the device 10 shown in FIG. 5, except for the addition of a further wing 44 to increase downforce on the device 10. The wing 44, which is in the form of an elevated wing, creates additional downforce to maintain close ground proximity of one or both of the lifting ramps to ensure efficient debris collection. The elevated wing 44 may also act as a debris retention mesh support, ensuring a retention mesh remains clear of the lifting ramp 16 enabling clear transition of collected debris to the catcher 14. In an alternative form, the device 10 may be provided with only a single aerofoil being an elevated wing 44 as shown in FIG. 6. Advantageously, the wing 44 may be elevated on one or more supports (one support at either end as shown in the example depicted in FIG. 6) to as to receive a stronger and unshielded airflow above the level of the lifting ramp 16.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge. 

1. A device for collecting debris from a surface, comprising a catcher and a lifting ramp, wherein the lifting ramp is located forward of the catcher such that when the device is moved over a ground surface, debris on the ground surface passes upwardly over the lifting ramp onto the catcher, wherein the lifting ramp is shaped as an aerofoil to create downforce on the lifting ramp toward the ground surface from air moving across the aerofoil under said movement.
 2. A device for collecting debris as claimed in claim 1, wherein the device includes an agitator forward of the lifting ramp and an opening between the agitator and the lifting ramp, whereby, under said movement over the ground surface, said debris on the ground surface passes through the opening and onto the catcher via the lifting ramp.
 3. A device for collecting debris as claimed in claim 1, wherein the catcher is a catcher platform.
 4. A device for collecting debris as claimed in claim 1, wherein the device includes a single aerofoil.
 5. A device for collecting debris as claimed in claim 1, wherein the device includes a plurality of aerofoils for creating downforce on the device toward the ground surface from air moving across the aerofoils under said movement.
 6. A device for collecting debris as claimed in claim 5, wherein the device includes a pair of aerofoils, including a first aerofoil in the form of said lifting ramp and a second aerofoil in the form of an additional lifting ramp mounted forwardly of said lifting ramp.
 7. A device for collecting debris as claimed in claim 6, further comprising an agitator forward of the lifting ramp and an opening between the agitator and the lifting ramp, whereby, under said movement over the ground surface, said debris on the ground surface passes through the opening and onto the catcher via the lifting ramp, wherein the additional lifting ramp is located intermediate of the opening such that a forward opening portion of the opening is located forward of the additional lifting ramp and a rearward opening portion of the opening is located rearward of the additional lifting ramp.
 8. A device for collecting debris as claimed in claim 1, wherein the device includes a tow hitch for attaching the device to a towing vehicle.
 9. A device for collecting debris as claimed in claim 1, wherein the device includes a generally planar member having at least a portion thereof defining an undersurface of the device formed of a conformable material such that when the device is moved over the ground surface with the undersurface in contact with the ground surface the undersurface is caused to locally conform to undulations in the ground surface.
 10. A device for collecting debris as claimed in claim 9, wherein the catcher is an upper surface of the device.
 11. A device as claimed in claim 9, wherein said portion is formed from a flexible layer.
 12. A device as claimed in claim 9, wherein said portion is formed from a mat of sinuous fibres.
 13. A device as claimed in claim 9, wherein said portion comprises artificial grass material.
 14. A device as claimed in claim 9, wherein said conformable material comprises a brush-like structure.
 15. A device as claimed in claim 9, wherein said conformable material has bristles being constituted, and positioned with respect to the opening, whereby when the device is moved over the ground surface with the bristles in contact therewith, debris on the ground surface is agitated by engagement with the bristles and caused to pass upwardly through the opening to the catcher for collection thereon.
 16. A device for collecting debris as claimed in claim 1, wherein the device includes a further aerofoil which is elevated above a level of the lifting ramp.
 17. A device for collecting debris from a surface, comprising a catcher and a lifting ramp, wherein the lifting ramp is located forward of the catcher such that when the device is moved over a ground surface, debris on the ground surface passes upwardly over the lifting ramp onto the catcher, wherein the device includes an aerofoil to create downforce on the lifting ramp toward the ground surface from air moving across the aerofoil under said movement.
 18. A device for collecting debris as claimed in claim 17, wherein the aerofoil is in the form of a wing mounted atop at least one support to support the aerofoil in an airflow above a level of the lifting ramp. 